Treatment of nitrocellulose



i- R; w. CAIRNS ETAL 2,382,130

TREATMENT OF NITROCELLULOSE Filed May 19, 1943 I l2\ El is I E5INVENTORS ROBERT w. CAIRNS RAPHAEL Ira-ream Patented Aug. 14, 1945 QTREATMENT OF NITROCELLULOSE Robert W. Cairns, Wilmington, Del.,andRaphael L. Stern, South River, N. J., assignors to Hercules PowderCompany, Wilmington, DeL, k a corporation of Delaware Application May19, 1943, Serial No 487,662

13 Claims. 260223) This invention relates to a method for conditioningfibrous nitrated cellulose so that it may be stored safely withoutdeterioration. It also relates to the product obtained by application ofthe method and to apparatus for carrying out the method.

Fibrous nitrated cellulose, especially the highly nitrated celluloseused for the preparation of smokeless powder, is maintained wet withwater for safe storage before use and in transit. However, the nitrogencontent ofv th wet nitrocellulose provides a condition which isconducive to growth of molds in the mass. Mold growths frequently spreadin a short time through stored masses of nitrocellulose with consequentdeterioration of the material.

In accordance with this invention, growth of molds in wet nitratedcellulose is prevented by distributing a lower aliphatic alcohol in thewet fibrous nitrated cellulose in a quantity to provide a solution ofaqueous alcohol wetting the fibers, the solution having an averagealcohol concentration between about 7% and about 45% by weight of thesolution. The resulting product, i. e., fibrous nitrated cellulose wetwith an aqueous alcohol solution in the range of concentrationmentioned, may be stored with the same safety as nitrated cellulose .wetonly with water and, at the same time, it cannot deteriorate due to moldgrowth. The treated fibrous mass has the further advantage of beingnon-freezing or resistant to freezing, obviating thawing operations.

The method in accordance with this invention is carried out onstabilized fibrous nitrocellulose,

wet with water, but usually freed of excess water such as by pressing orcentrifuging. This material is placed in a container and treated todistribute an alcohol therein, most conveniently with the aid ofapparatus which is a part of the present invention.

This apparatus is most readily described with reference to the drawingin which:

Figure 1 is a frontal view partly in section of the apparatus whichincludes a head and lance assembly for inserting the alcohol and meansfor operatively moving the assembly;

Figure 2 is a perspective View of the head and lance assembly; and

Figure 3 is a detailed view of a lance, partly in section.

Referring'to-Figure 1, which illustrates an apparatus in accordance withthis invention in a position of use, it will be seen that the appcomprises .a head I in which are mounted a plurality of lances 2. Thelances are hollow Wil ing a longitudinal passage 4 in each lance.- Thehead is provided with an interior passage or passage system 5 whichconnects with the longitudinal passage of each of the lances. The headis also provided with an inlet fitting 6 leading to the passage systemof the head and connected by a flexible conduit 1 to, a pump or othersource capable of providing a flow of the liquid to be distributed inthe fibrous mass to the head passages. Figure 1 shows the lances inposition extending into a barrel 8 which in normal operation is packed,with the fibrous mass. The apparatus further comprises means forforcing thelances into the fibrous mass and then upon completion of theoperation ofdistributingliquid in the mass, removing the lances. In theapparatus of Figure 1, this "comprises a connecting rod 9 connecting thehead to a piston' ID in a cylinder I l. The cylinder is provided withheads 12 provided with inlet and outlet fittings l3 connected to asuitable systemior providing a fluid under pressure, and for arrangingfor release of the fluid as required to operate the piston, andtherebyto lower and I raise the head'inwhich th lances are mounted with theforce required for operation.

' An arrangement of the-plurality of lances is shownin Figure 2 whichprovides a bottom view in perspective of the head and lance assembly.The particular assembly shown in Figure 2 comprises six lances insymmetrical arrangement supported by a circular head. Each lance isprovided with a plurality of apertures I4 leading from the outer surfaceto the hollow passage of the lance. The detailed construction of asuitable lance is shown in Figure 3. The lance consists of a rigidhollow tube provided with a sharp point and means for mounting the otherend in the head. A plurality of holes l4 leading to the hollow passagepermits escape of fluid forced into the hollow passage. The holes arespaced longitudinally along the lance and are placed on all sides of thelance. Preferably, the holes are spaced regularly and are at a distance,such as 3-6'inches from each other, to provide adequate distribution ofliquid-throughout the length of the lances. Preferably, the holes arecountersunk using a relatively shallow wide cut around each hole.Countersinking is valuable in the prevention of clog-- ging of the holeswhen operating with the fibrous nitrated cellulose since thenitrocellulose fibers readily cause plugging of ordinary drilled holes,due to their friable nature.

In operation, stabilized, washed, nitrated cellulose is placed in thewater wet condition in a container, such as a shipping barrel, and ispacked therein in the usual manner. Preferably, the

material is freed of excess water, for example by pressing orcentrifuging. It is desirable to press or centrifuge the wetnitrocellulose to a known water content. The plurality of lances is thenforced into the mass of fibrous nitrated cellulose and a known quantityof the alcohol is forced by pressure into themass. The pressure utilizedwill be sufiicient to force the alcohol into- I It will I usually bebetween about 25 pounds-and about 1 the lance's and thence into themass.

200 pounds per'square inch.v At such a pressure,

the desired quantity of the alcohol is .distributed 1 into the mass in afew seeonds. The alcohol may be in pure form or in solution in water.The quantity of alcohol utilized is such that upon; dilution by thewater in the still wet mass, the

solution resulting will have an average concenf,

tration between about 7% and about 45% by weight of alcohol of thesolution.

Desirably, the water wet fibrous nitrated cellulose, has a Water contentbetween about and about 40% by weight prior to insertion of the alcohol.

is then distributed in the mass to bring the concentration of theaqueous alcohol to 745% and 1 to bring the total volatile content of thefibrous mass to between about and about 45% preferably. between aboutand about 40%.'

The fibrous mass may contain more water than that mentioned at thebeginning of the operation, if desired, and following the distributiontherein of the amount of the alcohol required to obtain the desiredconcentration, excess solution may be removed, as by pressing orcentrifuging. from: the treated mass. However, this method is somewhatless convenient in view of the added operation involved.

The alcohol distributed in the mass shortly diffuses to form a solutionwith the 'water'therein. The solution is substantially uniform inconcentration. The concentration of the alcohol in.

Suflicient alcohol or'alcohol solution;

What we claim and desire to protect by Letters Patent is:

1 The method of conditioning and preserving fibrous nitrated cellulosesafely without substantial deterioration which comprises wetting thefibrous material with water containing in solution between about 7% andabout 45% by weight of the solution of a lower aliphatic alcohol andstoring the material wet with the said solution.

2. The method of conditioning and preserving fibrous nitrated cellulosesafely without substantial-deterioration which comprises wetting thefibrous material with water containing in solution between about 7% andabout 45 by weight 1 of the solution of ethyl alcohol, the watersolution being in quantity between about 20% and about'45% by weight oftheentire mass.

' I 3. The method of preserving fibrous nitrated of the mass to therange between about 13 and '27 F.

Ethyl alcohol is greatly preferred as the alcohol utilized forprevention of mold growth, since it:

is cheap and is usually utilized in later processing of the nitratedcellulose in the preparation of smokelessv powder. However, other loweraliphatic water-soluble alcohols such as methyl alcohol, propyl alcohol,isopropyl alcohol, nitroethanol, and the like, may be used.

is particularly useful for conditioning fibrous nitrated cellulosehaving a nitrogen content between about 12.4 and 14.1%, this being thetype used in smokeless powder manufacture, as such nitrated cellulosemust be stored for safety wet with water. However, the method may alsobe applied to soluble fibrousnitrated'cellulose types having a nitrogencontent between about 10.5% and 2.4%.

Themethod in accordance with this invention solution of ethyl alcohol,the water solution being i in a quantity between about 20% and about 45%by weight of the entire mass.

5. The method of conditioning and preserving fibrous nitrated cellulosesafely without substantial deterioration whichcomprises forming a massof the fibrous nitrated cellulose wet with essentially water,introducing-a lower aliphatic water-soluble alcohol .into the wet massat a plurality of points in' the mass in a quantity suflicient to form asolution containing between about 7% and about 45% of. the alcohol upondilution by the water, permitting the alcohol to diffuse in the mass andmix with the' water,

therein to form a solution wetting the fibers having an averageconcentration between about 7% and about 45%, and storing the resultingfibrous nitrated cellulose. v

6. The method of conditioning and preserving fibrous nitrated cellulose'safely Without substantial deterioration which comprises'forming a massof the fibrous nitrated cellulose wet with water in a quantity betweenabout l5and about 40% of the wet mass, introducing a loweraliphaticalcohol into the wet mass at a plurality of points in the mass in aquantity sufficient to increase the liquid content of the mass tobetween about 20% and about 45% of the resulting wet mass and to form awater solution in the mass having an average concentration of thealcohol by weight between about 7% and about 45% of the solution,permitting the alcohol to diffuse in the mass and to mix with the watertherein, and storing the resultingfibrous nitrated cellulose.

7. The method of conditioning and preserving fibrous nitrated cellulosesafely without substantial deterioration which comprises forming a massof the fibrous nitrated cellulose wet with essentially water,introducing ethyl alcoholinto the wet mass at a plurality of points inthe mass in a quantity sufficient to form a solution containing betweenabout 7% and about 45% of the alcohol upon dilution by the water,permitting the alcohol to diffuse in themass and mix with the watertherein to form a solution wetbetween about 7% and about 45%, andstoring the resulting fibrous nitrated cellulose. 8. The method ofconditioning and preserving fibrous nitrated cellulose safely withoutsubstantial deterioration which comprises forming a mass of the fibrousnitrated cellulose wet with water in a quantity between about 15 andabout 40% of the wet mass, introducing ethyl alcohol into the wet massat a plurality of points in the mass in a quantity sufficient toincrease the liquid content of the mass to between about 20% and about45% on the resulting wet mass and to form a water solution in the masshaving an average concentration of the alcohol by weight between about7% and about 45% of the solu-.

tion, permitting the alcohol to diffuse in the- 11. A mass of fibrousnitrated cellulose suitable for safe prolonged storage consistingessentially of nitrated cellulose fibers wet with water containing insolution between about 7% and about by weight of the solution of a loweraliphatic alcohol, the said mass containing between about 20% and about45% by weight of the water solution.

12. A mass of fibrous nitrated cellulose suitable for safe prolongedstorage consisting essentially of nitrated cellulose fibers wet withwater containing in solution between about 7% and about 45% by weight ofthe solution of ethyl alcohol, the said mass containing between about20% and about 45% by weight of the water solution.

13. The method of conditioning and preserving fibrous nitrated cellulosesafely without substantial deterioration which'comprises wetting thefibrous material with water containing in solution between about 7% andabout 45% by weight of the solution of a lower aliphatic alcohol, thewater solution being of substantially uniform concentration throughoutthe fibrous material, and storing the material wet with the saidsolution.

ROBERT W. CAIRNS. RAPHAEL L. STERN.

